Compositions

ABSTRACT

A solid, ingestible composition comprising: a. an alginate; b. a bicarbonate and/or carbonate; and 
         c. a C 2 -C 5  polyol or poly(C 2 -C 5  alkylene glycol).

The present invention relates to pharmaceutical compositions, and in particular to composition for the treatment of reflux oesophagitis, gastritis, dyspepsia or peptic ulceration or for use as a sustained releasing or targeted delivery compositions.

Reflux oesophagitis occurs when small amounts of gastric juice, food and/or bile acids pass into the lower part of the oesophagus and cause oesophageal inflammation accompanied by pain which may manifest itself in the form of heartburn.

One approach to the problem of reflux oesophagitis has been to administer a preparation which on contact with gastric acid generates a carbonated gelatinous foam or raft which floats on the stomach contents. When reflux occurs it is this raft which precedes the stomach contents into the oesophagus, thus protecting the mucosa from further irritation. Known preparations of this type include liquid preparations comprising sodium alginate, sodium or potassium bicarbonate and calcium carbonate. Such compositions are sold under the trade marks GAVISCON and GAVISCON ADVANCE and are described in GB-A-1,524,740 and WO 95/11668.

Other such preparations are those in solid form, for example in the form of powders or tablets, such as those which again are sold under the trade mark GAVISCON. Such preparations comprise alginic acid, sodium bicarbonate and calcium carbonate. The alginic acid and the bicarbonate and carbonate react in the aqueous environment of the mouth to form an alginate foam, which is then swallowed. In the acidic stomach environment the alginate is converted back into insoluble alginic acid, which then forms the raft on top of the stomach contents.

It has been found that solid compositions which foam in the mouth are difficult, and sometimes unpleasant, to swallow. In order to provide a non-foaming, solid composition we have tried to replace the alginic acid by an alginate. However, we have found that such compositions have extremely poor mouth feel. The alginate is sticky and causes the composition to stick to the palate, and especially to the teeth.

We have surprisingly found that the mouth feel and stickiness of such compositions can be improved by including a further component in the composition.

Accordingly the present invention provides a solid, ingestible composition comprising:

-   a. an alginate; -   b. a bicarbonate and/or carbonate; and -   c. a C₂-C₅ polyol or poly(C₂-C₅ alkylene glycol) having a molecular     weight of at least 6000.

The composition of the present invention has less foaming than the tablets currently sold under the trade mark GAVISCON since it comprises an alginate rather than alginic acid. It also has a good mouth feel and does not stick to the teeth as much as a composition which does not comprise a polyol or polyalkylene glycol.

The composition of the present invention comprises an alginate. Any alginate may be used, but it is especially desirable to use an alkali metal salt of an alginate, such as sodium or potassium alginate. Preferably a low viscosity grade of the alginate is used. These are generally grades of alginate for which the viscosity of a 10% weight/volume aqueous solution, when determined on a Brookfield RVT viscometer using spindle number 3 at 20 r.p.m. at 20° C., falls within the range of 200 to 1,500 mPa·s. An example of a suitable commercial grade of low viscosity sodium alginate is Protanal LFR 5/60, obtainable from FMC BioPolymer. High viscosity grades of alginate may also be used. These are generally grades alginate for which the viscosity of a 1% weight/volume aqueous solution, when determined on a Brookfield RVT viscometer using spindle number 3 at 20 r.p.m. at 20° C., is above 500 mPa·s. An example of a suitable commercial grade of high viscosity sodium alginate is Protanal SF200, also obtainable from FMC BioPolymer

The compositions of the present invention generally have a content of alginate of from 2 to 90 wt %, preferably 5 to 50 wt %, based on the total weight of the composition.

The compositions of the present invention also comprise a bicarbonate and/or carbonate. Examples of bicarbonates are alkali metal bicarbonates such as sodium and potassium bicarbonate and alkaline earth metal bicarbonates. One or two or more different bicarbonates may be used. Examples of carbonates are alkali metal carbonates such as sodium and potassium carbonate and alkaline earth metal carbonates such as calcium and magnesium carbonate. Further examples are aluminium carbonate and mixed alkali metal carbonates such as sodium glycine carbonate. One or two or more different carbonates may be used. Furthermore one or more bicarbonates may be used with one or more carbonates. Especially preferred combinations are sodium and/or potassium bicarbonate and calcium carbonate.

The carbonate and/or bicarbonate are present in amounts such that they provide an adequate volume of gas (carbon dioxide) to float the gel produced when the alginate contacts the gastric acid in the stomach. The rigidity and thickness of the carbonate raft will depend, for example, upon the relative amounts of carbonate and/or bicarbonate and on the grade of the alginate.

If used alone, the bicarbonate is generally present in the compositions of the present invention in an amount of from 1.5 to 35 wt %, preferably 2 to 15 wt %, most preferably 3 to 10 wt %. If used alone, the carbonate is generally present in the compositions of the present invention in an amount of from 0.2 to 55 wt %, preferably 0.5 to 10 wt %, most preferably 1 to 4 wt %.

Preferably the bicarbonate and carbonate may also be present together in the composition, preferably from 1 to 20 wt %, for example in a total amount of from 1 to 40 wt %, preferably 1 to 12 wt %. Approximately equal amounts of the bicarbonate and carbonate may be present in the composition. Alternatively, the composition may comprise more bicarbonate than carbonate. The weight ratio of bicarbonate to carbonate in the composition may be from 1:1 to 2:1.

The compositions of the present invention also comprise a C₂-C₅ polyol or poly(C₂-C₅ alkylene glycol). Suitable polyols have 2, 3, 4 or 5 carbon atoms and contain 2 or more hydroxy groups, for example 2, 3, 4 or 5 hydroxy groups. Examples of suitable compounds are ethylene glycol, propylene glycol, glycerol and erythritol.

The poly(C₂-C₅ alkylene glycol) is preferably a polyethylene glycol or polypropylene glycol. The polyalkylene glycol may comprise any number of alkylene glycol units, for example having a molecular weight of at least 6000. Polyalkylene glycols may be liquid or solid at room temperature (20° C.). It is preferred to use the solid form, particularly in the form of a free-flowing powder, for ease of handling and incorporation into the blend.

The polyol or poly(C₂-C₅ alkylene glycol) is generally present in the compositions of the present invention in an amount of from 1 to 50 wt %, preferably from 1 to 15 wt %, preferably 1.5 to 10 wt %, most preferably 2 to 6 wt %.

The polyol or poly(C₂-C₅ alkylene glycol) and the alginate may, for example, be present in the composition of the present invention in a weight ratio of from 2:1 to 1:25, preferably from 1:4 to 1:12.5.

The compositions of the present invention may also comprise further, optional components.

For example, the compositions of the present invention preferably comprise a source of divalent and/or trivalent metal ions. Such ions strengthen the raft formed in the stomach. Suitable metal ions are calcium and aluminium. The ions may be provided as part of the bicarbonate and/or carbonate, but may also comprise other anions if desired. For example, suitable sources of calcium ions are calcium carbonate, lactate, chloride, gluconate, phosphate, hydrogen phosphate, sulfate, tartrate or citrate, and suitable sources of aluminium ions are aluminium carbonate, lactate, glycinate or phosphate, aluminium magnesium carbonate, hydroxide or magaldrate, aluminium sodium carbonate hydroxide or aluminium sodium silicate. If used, the calcium ions are preferably present in an amount of from 8 to 800 parts, and the aluminium ions are preferably present in an amount of from 2 to 500 parts, per 500 parts by weight of alginate.

The compositions of the present invention may also comprise a preservative to prevent contamination and subsequent deterioration by micro-organisms. Examples of suitable preservatives are methyl, ethyl, propyl and butyl para-hydroxybenzoates and their salts, which are preferably used in combinations, for example methyl and propyl or ethyl and butyl. The compositions of the present invention do not need to include such a preservative, but if a preservative is present it may be used in an amount of, for example, up to 0.5 wt %, based on the total weight of the composition.

The compositions of the present invention may also comprise one or more colourings, sweetenings, flavourings, pH adjusting ingredients and fillers. When the compositions of the present invention are intended for use as sustained releasing compositions they will also comprise at least one active ingredient suitable for specific delivery to the stomach, such as a drug. Examples of suitable drugs are analgesics (e.g. sucacetaminophen, ibuprofen, naproxen, diclofenac, ketoprofen, choline salicylate, benzydamine, buprenorphine, hydrocortisone, betamethasone); decongestants (e.g. pseudoephedrine, phenylephrine, oxymetazoline, xylometazoline); cough suppressants (e.g. dextromethorphan, codeine, pholocodine); expectorants (e.g. guaiphenesin, n-acetylcysteine, bromhexine); antiseptics (e.g. triclosan, chloroxylenol, amylmetacresol, hexylresorcinol, dichlorobenzyl alcohol, benzyl alcohol); cardiovascular agents (e.g. glyceryl trinitrate); local anaesthetics (e.g. benzocaine, lignocaine); antacid agents (e.g. calcium carbonate, sodium bicarbonate, magnesium trisilicate, aluminium hydroxide, magaldrate,); antiulcer agents (e.g. carbenoxolone, sucralfate, cimetidine, ranitidine, nizatidine, famotidine, omeprazole, pantoprazole); antihistamines (e.g. loratidine, terfenadine, diphenhydramine, chlorphenhydramine, triprolidine, acrivastine); antinausea agents (e.g. prochlorperazine, sumatriptan); bowel regulatory agents (e.g. diphenoxylate, loperamide, sennosides); antifungal agents (e.g. clotrimazole); antimicrobial agents and antibiotics (e.g. fusafungine, tyrothricin).

It is also possible for the compositions of the present invention to comprise alginic acid, although this is not preferred since it could cause undesirable foaming in the mouth.

The compositions of the present invention may be in any solid form. For example they may be in the form of a tablet, such as a chewable tablet. They may also be in the form of a chewable gum, a confectionary such as a fudge or boiled sweet or in the form of particles or granules, for example free-flowing or packed in a capsule, for example a soft or hard gel capsule. The composition of the present invention may be used in a method of treatment of the human or animal body by therapy, especially use in the treatment of reflux oesophagitis, gastritis, dyspepsia or peptic ulceration or for use as a sustained releasing or targeted delivery composition.

The composition of the present invention may be used in the manufacture of a medicament for the treatment of reflux oesophagitis, gastritis, dyspepsia or peptic ulceration or for use as a sustained releasing or targeted delivery composition.

The composition of the present invention may be used in a method of treating reflux oesophagitis, gastritis, dyspepsia or peptic ulceration or for sustained releasing or targeting a delivery composition, which comprises orally administering to a subject in need thereof or liable to need an effective amount of the composition.

The composition is generally administered in an amount of from 100 to 2000 mg alginate per dose.

The compositions of the present invention may be prepared by simply mixing the ingredients. It is especially preferred to mix the ingredients together in particulate form and then granulate or agglomerate the particles using a suitable granulating agent such as water, a C₂ to C₄ alcohol such as ethanol or isopropanol, or a mixture thereof. This is especially suitable when the PEG used is naturally a solid. It is also possible to granulate the remaining ingredients with PEG as a granulating agent when it is in liquid form. Additional granulating binders may also be used, for example povidone, a cellulose derivative such as HPMC or starch paste. A preferred starch paste uses water as the granulating solvent, and povidone is generally used with an ethanol or isopropanol solvent. We have surprisingly found that when a wet granulation is carried out, the amount of polyol or polyalkylene glycol can be reduced while retaining a satisfactory mouthfeel. A normal granulation process may need a weight ratio of polyol or polyalkylene glycol to alginate of up to about 1:1. However, using a wet granulation process enables the weight ratio of polyol or polyalkylene glycol to alginate to be reduced to less than 0.25:1, especially less than 0.15:1, while retaining a satisfactory mouthfeel.

One or more of the components may be added after granulation. In particular the polyol or polyalkylene glycol may be added after granulation, although this is not preferred since an increased amount of this component may be required to achieve a suitable mouth feel. It is preferred to avoid the use of excessive amounts of polyol or polyalkylene glycol since the amount of this component which can be ingested may be limited by regulatory authorities.

In a preferred process for preparing the composition of the present invention, the alginate, carbonate and/or bicarbonate and polyol or polyalkylene glycol are granulated together, dried and screened prior to mixing in any further components. It is also possible, for example, to granulate only the alginate and the polyol or polyalkylene glycol prior to adding the remaining components.

The present invention is further described in the following Examples.

EXAMPLES Example 1

The following particulate components (each having a maximum particle size of 1 mm) were mixed together in a high shear mixer for 1 minute: Sodium Alginate LFR 5/60 250 g  Sodium bicarbonate 133.5 g   Calcium carbonate 80 g PEG 20,000 30 g

The mixture was then granulated in a granulator using 75 ml distilled, deionised water as a granulating agent.

The granules were then dried in a fluid bed drier at 40° C. for 20 minutes and subsequently milled firstly through a 610 μm screen and secondly through a 457 μm screen using a Quadro Comill. The milled granulate was then blended with the following ingredients in a low shear tumble blender for 5 minutes: Mannitol 522.75 g   Crospovidone (dispersant)  55 g Flavour 1 5.5 g Flavour 2 1.1 g Acesulfame K 5.5 g Aspartame 1.65 g 

Finally, 15 g magnesium stearate was added to the blender, and blending was continued for a further 2 minutes.

The granules were then compressed into tablets each containing 250 mg or 500 mg sodium alginate. The tablets were found to have a smooth, slightly chewy texture with no significant toothpacking or gummy residue.

Example 2

250 and 500 mg tablets were prepared following the procedure of Example 1 except for using the following components: Sodium Alginate LFR 5/60 250 g  Sodium bicarbonate 133.5 g   Calcium carbonate 80 g PEG 20,000 30 g Mannitol 516.5 g   Crospovidone 55 g Flavour 10 g Aspartame 10 g Magnesium stearate 15 g

Comparative Example 1 and Examples 3 to 7

A Comparative test was carried out to illustrate the beneficial effects of a polyalkylene glycol on the mouthfeel of a composition.

The following compositions were prepared: Ingredient EXAMPLES (mg) Comparative 1 3 4 5 6 7 Protanal 520 500 500 500 500 500 LFR 5/60 NaHCO₃ 177 170 170 170 170 170 Mannitol 1178 950 600 950 1125 300 Mg-stearate 31 30 30 30 30 30 Kollidon 104 — — — — — 90 F PEG 20000 — — 700 350 175 1000 PEG 3000 — 350 — — — — Total 2010 2000 2000 2000 2000 2000 weight (mg) PEG:Alginate — 1:1.43 1:0.71 1:1.43 1:2.86 1:0.5 Mouthfeel Very Sticky Satisfactory Not Drying Creamy, Quick in mouth + toothpacking for sticking or initially, not dispersing. not toothpacking. slightly sticky Very sticking Slightly gritty. clean in oily/creamy Then the creamy. Not mouth sticky i.e. not sticky or toothpacking

Comparative Example 2 and Example 8

Tablets produced by the method set out below were then evaluated for their mouthfeel. Example Comparative 2 Ingredient mg/tablet mg/tablet Sodium alginate 250.00 250.00 LFR5/60 Sodium bicarbonate 133.50 133.50 Calcium carbonate 80.00 80.00 Mannitol 607.75 432.75 Polyethylene Glycol 0.00 175.00 20000 Flavour 1 5.50 5.50 Flavour 2 1.10 1.10 Sweetener 1 5.50 5.50 Sweetener 2 1.65 1.65 Magnesium stearate 15.00 15.00 Tablet weight 1100 mg 1100 mg Processing

Batch size produced 550 g

1. Blend together ingredients except magnesium stearate for 5 minutes using a Turbula T2C tumble mixer.

2. Add the magnesium stearate and blend for a further 2 minutes.

3. Compress into tablets using the Riva Piccola tablet press fitted with 16 mm FBE punches.

Tableting of the composition of Comparative Example 2 that did not contain PEG was poor, with evidence of lamination and capping.

The organoleptic properties of these tablets were assessed in the laboratory: Tooth- After Example packing Mouthfeel Taste taste Overall Example 8 Very Drier, Pleasant, None OK - slight crisper. mint acceptable Tablet broke up quickly. Comparative Worst of Drying, Pleasant, None Poor - 2 all cloying mint unacceptable batches pasty, chewy & sticky

To check for raft formation properties and the appearance of the rafts, four crushed tablets (total 1 g sodium alginate) were mixed with 20 ml of water and poured into a 250 ml beaker containing 150 ml 0.1M HCl at 37° C. The ability to form a coherent foamy floating gel “raft” on the surface of the acid over 30 minutes was observed.

In both cases a floating raft was rapidly formed. This was continuous across the beaker surface and was resistant to rupture. No difference was observed between the two formulations.

Addition of PEG to the composition therefore has a significant effect on the mouthfeel of the product without affecting the ability to form a reflux-suppressing raft.

Example 9

Tablets containing the following components were prepared. Sodium aliginate LFR5/60 250.00 mg  Sodium bicarbonate 133.50 mg  Calcium carbonate 80.00 mg Mannitol 516.50 mg  Polyethylene Glycol 20000 30.00 mg Crospovidone 55.00 mg Mint Flavour 10.00 mg Sweetener 10.00 mg Magnesium stearate 15.00 mg Tablet weight  1100 mg Process

1. Granulate components

1.1 Add Sodium alginate LFR5/60, Sodium bicarbonate, Calcium carbonate, and Polyethylene Glycol 20000 to food processor Bowl (Magimix 3000 mixer fitted with large bowl).

1.2. Turn on processor and blend the powders for 2 minutes.

1.3 Granulate by spraying in water until a wet mass begins to form (approximately 70-110 g water).

1.4 Dry the granules in a fluid bed drier (Aeromatic Strea 1) at 40° C. inlet air temperature.

1.5 screen the dried granules using Quadro Comill mill fitted with a 457 μm screen.

1.6 sieve the granules through a 850 μm sieve

2. Tableting mix

2.1 Take the granules and the appropriate amount of the remaining ingredients except the magnesium stearate and tumble mix for 5 minutes.

2.2 Add the magnesium stearate and tumble mix for a further 2 minutes.

3. Tableting

3.1 Tablet the resulting tablet blend using the Riva Piccola bench top rotary tablet press fitted with 16 mm FBE punches.

It was found that wet granulation of the components with the PEG enabled a reduced amount of PEG to be used as compared with the dry granulation of Example 8, while still retaining an acceptable mouthfeel.

Example 10

Tablets were prepared from the following compositions, using the process described in Example 9. Sodium alginate LFR5/60 (sorbitol free) 500.00 mg Potassium bicarbonate, medium granular 100.00 mg Calcium carbonate 100.00 mg Polyethylene glycol 20,000  60.00 mg Mannitol 1260.00 mg  Crospovidone 110.00 mg Mint flavour  20.00 mg Sweetener  20.00 mg Magnesium stearate  30.00 mg Total 2200.00 mg 

The tablets were produced to a weight of 500 mg using 22 mm flat bevel edge tooling.

These tablets gave satisfactory mouthfeel and raft formation and texture were at least as good as those of Example 9.

Example 11

Example 10 was repeated but using the following compositions: Sodium Alginate LFR 5/60 250 g  Sodium bicarbonate 133.5 g   Calcium carbonate 80 g PEG 20,000 30 g Mannitol 571.5 g   Mint flavour 10 g Sweetener 10 g Magnesium stearate 15 g

The tablets produced were considered to have a better mouthfeel than those of Example 10, even though they did not contain Crospovidone.

Examples 12 to 17

Tablets were prepared from the following compositions: 12 13 14 15 16 17 mg/ mg/ mg/ mg/ mg/ mg/ Ingredient tablet tablet tablet tablet tablet tablet Sodium 250.00 250.00 250.00 250.00 250.00 250.00 alginate LFR5/60 Sodium  50.00 250.00  50.00 133.00 133.00  50.00 bicarbonate Calcium  25.00  10.00 100.00  20.00  80.00 100.00 carbonate Polyethylene 175.00 175.00 175.00 175.00 — — Glycol 20000 Polyethylene — — — — 175.00 175.00 Glycol 3000 Crospovidone  1.10  1.10  1.10  1.10  1.10  1.10 Flavour  5.50  5.50  5.50  5.50  5.50  5.50 Sweetener  1.65  1.65  1.65  1.65  1.65  1.65 Magnesium  15.00  15.00  15.00  15.00  15.00  15.00 stearate Mannitol Qs qs qs qs qs qs Tablet weight   1100 mg   1100 mg   1100 mg   1100 mg   1100 mg   1100 mg

Example 18

Tablets were prepared from the following compositions: Ingredient mg/tablet Sodium alginate 500.00 Potassium bicarbonate 100.00 Calcium carbonate 100.00 Polyethylene glycol 60.00 20,000 Mannitol 1370.00 Flavouring 20.00 Sweetener 20.00 Magnesium Stearate 30.00 Total 2200.00 

1. A solid, ingestible composition comprising: a. an alginate; b. a bicarbonate and/or carbonate; and c. a C₂-C₅ polyol or poly(C₂-C₅ alkylene glycol) having a molecular weight of at least 6,000 and present in the composition in an amount of from 1 to 50 weight %.
 2. A composition according to claim 1 wherein the polyalkylene glycol is polyethylene glycol (PEG).
 3. A composition according to claim 1 wherein the alginate is sodium alginate.
 4. A composition according to claim 1 wherein the bicarbonate is sodium bicarbonate.
 5. A composition according to claim 1 wherein the carbonate is calcium carbonate.
 6. A composition according to claim 1 which is in the form of a tablet.
 7. A composition according to claim 1 for use in a method of treatment of the human or animal body by therapy.
 8. A composition according to claim 1 for use in the treatment of reflux oesophagitis, gastritis, dyspepsia or peptic ulceration or for use as a sustained releasing or targeted delivery composition.
 9. Use of a composition according to claim 1 in the manufacture of a medicament for the treatment of reflux oesophagitis, gastritis, dyspepsia or peptic ulceration or for use as a sustained releasing or targeted delivery composition.
 10. Use of a composition according to claim 1 for the treatment of reflux oesophagitis, gastritis, dyspepsia or peptic ulceration or for use as a sustained releasing or targeted delivery composition.
 11. A method of treating reflux oesophagitis, gastritis, dyspepsia or peptic ulceration or for sustained releasing or targeting a delivery composition, which comprises orally administering to a subject in need thereof or liable to need an effective amount of a composition according to claim
 1. 12. A process for preparing a composition according to claim 1 which comprises mixing together the alginate, the bicarbonate and/or carbonate and the polyol or polyalkylene glycol.
 13. A process according to claim 12 wherein the components are granulated together in a wet granulation process.
 14. A process according to claim 13 wherein the weight ratio of the polyol or polyalkylene glycol to the alginate is less than 0.25:1. 